Does scant hematochezia necessitate the performance of total colonoscopy?

Controversy exists as to whether all patients with lower intestinal bleeding need to undergo total colonoscopy. This study compares the prevalence of colonic neoplasms in patients reporting scant hematochezia with the prevalence in controls.

Structured interviews were carried out with 4265 consecutive patients referred for colonoscopy. Of these, 468 patients had scant hematochezia, 299 had occult rectal bleeding and 57 reported dark rectal bleeding. Patients with scant hematochezia were matched for age and sex with those having no risk factors for colorectal neoplasms. For all groups, we determined the prevalence of adenomas and cancers below and above 50 cm.

Colonic neoplasms were found in 18 % of patients with scant hematochezia and in 7.5 % of controls. However, most of these tumors were located within the reach of a sigmoidoscope. Compared with controls, patients with scant hematochezia had no increased risk for proximal neoplasms (odds ratio [OR] = 1.2), while this risk was significantly increased in patients with occult rectal bleeding (OR = 3.1) and patients who had observed maroon-colored blood in their stool (OR = 4.8).

Flexible sigmoidoscopy appears to be a sufficient work-up for young patients who have observed trace amounts of bright red blood on the surface of their stool.